(1) The Secretary may, by legislative instrument, determine:
(a) the assessment methods and standards to be applied in working out the energy efficiency rating for a building; and
(b) the assessment methods and standards to be applied in performing a lighting energy efficiency assessment for the building; and
(c) the assessment methods and standards to be applied in performing a lighting energy efficiency assessment for the area; and
(d) the circumstances in which a building or an area of a building is exempt for the purposes of section 17A.
(2) Without limiting subsection (1), the Secretary may determine an assessment method or standard by applying, adopting or incorporating, with or without modification, any matter contained in any other instrument or writing as in force at a particular time or as in force from time to time.